“…The mean quality score of internal validity was 4.5/7 ( SD = 1). All but five studies (Beck et al., ; Blackbourn & Blackbourn, ; Chovan & Morrison, ; Jones, ; O'Such, Havertape, & Pierce, ) satisfied more than half of the external validity criteria. More precisely, in the reviewed studies, the most frequently satisfied criteria were adequate information regarding age/grade (20/21, 95%), sex (15/21, 71%), level of intellectual disability (13/21, 62%), recruitment setting (17/21, 81%) and school placement (20/21, 95%).…”